We'd like to be able to record video for reference on a separate track just like we can now record audio.

Here is a working example on a different application:
https://support.rokoko.com/hc/en-us/articles/4410423223953-Video-Reference

This isn't for generating mocap from data from the video.

The purpose of this function would to be able to start and stop reference video recording and sync it automatically without the need for an external recorder.